An assembling process of a semiconductor device, such as an IC or the like, comprises the steps of: cutting and separating (dicing) a semiconductor wafer and the like into respective chips, after patterning; mounting the chips on a substrate or the like; and sealing them with a resin or the like.
In the dicing step, a semiconductor wafer is adhered and fixed by an adhesive tape in advance, and then it is diced along a chip shape. In the mounting step, the chip is peeled off (picked up) from the adhesive tape and then fixed on a substrate or the like with an adhesive agent for adhering and fixing.
The tapes used for the above purposes include a usual pressure-sensitive adhesive-type tape, and a tape having a reduced adhesive force when it is hardened or cured by radiation, such as ultraviolet (UV) rays, electronic rays, and the like. Both of these types of tapes are required to have sufficient adhesive force so that the tape is not peeled off from the wafer upon dicing, and they are also required to have peeling capability to be easily peeled off from the wafer upon picking up.
Further, in the mounting step, sufficient adhesive force is required between the chip(s) and the substrate and the like.
There are suggested a variety of adhesive or adhesion tapes that are equipped with both of the function of a dicing adhesive tape used in the above process, and the function of an adhesive on a substrate and the like, which tapes are improved in the coating workability of the adhesive, and which simplify the whole process.
These adhesive tapes enable a so-called direct die bonding for, after dicing, picking up a chip with a removable adhesive layer adhered on the rear side of the chip, mounting the chip on a substrate or the like, and curing and adhering the chip by heating or the like. By these adhesive tapes, the coating process of an adhesive can be omitted.
However, the removable adhesion agent or adhesive agent used for these adhesive tapes is in a coating liquid state with low viscosity and low wettability to a tape base, and thus it has the problem of poor yield. Further, the above adhesion or adhesive agent is low in adhesion strength, compared with an existing adhesive or bonding agent for die bonding. Thus it is difficult to obtain reliability from the above adhesion or adhesive agent.
As means to obtain adhesion reliability and provide dicing performance, it is proposed to use a laminate of a die bonding adhesive layer and a dicing tape. However, this laminate-type tape has the problem that it is difficult to control the peeling ability between the adhesive and the dicing tape. A die bonding adhesive with high adhesion reliability generally requires heat adhesion upon temporarily fixing it to a wafer. However, the laminate-type tape has the problem of increase of peeling ability between the dicing tape and the die-bonding-sheet adhesive layer due to such a heat adhesion, thereby causing a raise of the pickup failure ratio after the dicing.
Further, it is also proposed that a die bond sheet is heat-adhered to a wafer in advance, and a dicing tape is laminated to the die bonding adhesive layer adhered to the wafer, before use. Also, in this case, a surface protective tape for back-grinding is usually bonded to a side of the wafer on which no die bonding sheet or dicing tape is bonded. To peel the surface protective tape from the wafer by lowering the adhesive force of the surface protective tape, a heat treatment is generally carried out. The heating temperature is generally about 40° C. or more, for example, about 60° C. Similarly to the above, this causes the problem of increased peeling force between the die bonding adhesive layer and the dicing tape.